Thread safety in Java class

Question

Why is this java class not Thread safe.

class TestClass {  
   private int x;

   int get() {
       return x;
   }

   void set(int x) {
       this.x = x;
         


        

Answer 1

When you have two method modifying/accessing a non-volatile variable it is never thread safe. If you want to have just one method you can try :

synchronized int getAndSet(int x, boolean set) {
    if (set) this.x = x;
    return this.x;   // param x is for set
}